Keying means for draft controls



June 1967 L. F. PFls'l 'ER KEYING MEANS FOR DRAFT CONTROLS Filed April 29, 1965 United States Patent O f 3,327,945 KEYING MEANS FOR DRAFT CONTROLS Leo F. Pfister, Mendota, ill, assignor to Conco Engineering Works, inc., a corporation of Illinois Filed Apr. 29, 1965, Ser. No. 451,744 12 Claims. (Cl. 236-45) This invention relates to barometric draft controls, and more specifically, to means for insuring proper installation of a barometric draft control on a fuel burning appliance.

Barometric draft controls are commonly used on fuel burning appliances such as incinerators and heating units. Whether the draft control he of the single acting type or the double acting type, it is intended to regulate and maintain the draft in the flue receiving the products of combustion from the fuel burning appliance at a substantially constant value. Double acting controls additionally relieve overpressure in the flue. If the draft is not maintained at substantially constant value, depending upon the type of appliance, one or more problems often preclude efficient and safe operation of the appliance. For example, with an excessive draft, the products of combustion may pass through the heat exchange section of a heating unit at a higher velocity than is desired because of the increased volume of the gases. When this occurs, the gases will not contact the heat exchanger surfaces for a sufficiently long period of time to allow maximum heat to be absorbed from them, and fuel is wasted. Too little draft can cause poor combustion so that excessive carbon monoxide is present in the products of combustion. In the case of both heating units and incinerators, such excessive carbon monoxide presents a very real danger to the life of the user of the appliance as well as to those persons occupying the building in which the appliance is located. Furthermore, in the case of a heating unit, too little draft and the accompanying poor combustion may cause the occurrence of free carbon or soot which will be deposited on the walls of the heat exchanger of the appliance. Since soot is a poor conductor of heat, the accumulation of it upon the heat exchanger walls results, in ineflicient heat exchange and wasted fuel. Finally, downdrafts or overpressure in the stack will affect the flame in the fuel burning appliance. Such overpressures often lead to the choking of the flame of the fuel burning appliance due to lack of oxygen. This, too, results in improper operation of the fuel burning appliance that may endanger the user thereof.

The use of barometric draft controls to obviate such problems is obviously of great importance from both the standpoint of safety and efficiency of the fuel burning appliance. To achieve such beneficial results, it is highly important that a barometric draft control be properly installed on the fuel burning appliance, for the common types of barometric draft controls currently in use are of such a nature, that if improperly installed, they are at best ineffective and at worst totally inoperative. For example, a typical barometric draft control includes a gate that is biased about a pivot point by means of weights or the like which are chosen to control the attitude of the gate relative to its pivot in relation to the draft requirements of a fuel burning appliance. Accordingly, if the housing in which the gate is pivotally mounted is connected to a fuel burning appliance in any one of several positions wherein the influence of gravity on the weight is negated or reversed, the proper biasing function of the weights is lost or is reversed. As a result, little or no control is maintained over the attitude of the gate within the housing and accordingly, the gate cannot act to regulate the draft in the flue of the fuel burning appliance. This, in turn, results in low operating efficiency of the fuel burning appliance and/or an unsafe operating condition, as previously mentioned.

3,327,945 Patented June 27, 1967 While it is relatively easy to properly install a barometric draft control, oftentimes inexperienced persons, such as homeowners installing their own fuel burning appliance, may connect the draft control to the fuel burning appliance in an improper manner. Similarly, an experienced workman who is being hurried for one reason or another may inadvertently install the barometric draft control improperly. Of course, when this is done the attendant evils are present.

It is, therefore, a principal object of the invention to provide a barometric draft control including means for facilitating proper installation of the control upon a fuel burning appliance.

Another object of the invention is the provision of such a control including means for precluding improper installation of the control upon a fuel burning appliance.

More specifically, it is an object of the invention to provide a barometric draft control including keying means which are received in complementary means on the fuel burning appliance or the flue associated therewith.

Another object of the invention is the provision of such keying means including a slot for receiving a tab integrally struck from the mating member.

Another object of the invention is to provide such keying means wherein a projection on one of the members is received in a slot on its mating member.

Another object of the invention is the provision of such keyingmeans in a barometric draft control wherein the keying means comprise an aperture on one of the members for reception of a pin on the mating member.

Another object of the invention is the provision in a barometric draft control of keying means wherein one member is formed with a groove that is adapted to nest with a complementary groove on the mating member.

Another object of the invention is the provision in a barometric draft control of such keying means wherein the keying means are permanently aflixed to a member such that they may not be removed to defeat the purpose thereof.

Other objects and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings in which:

FIGURE l is a side elevation of a fuel burning appliance with a portion thereof broken away and having a form of the invention mounted thereon;

FIGURE 2 is an expanded view of the form of the invention shown in FIGURE 1;

FIGURE 3 is a fragmentary expanded view of another form of the keying means of the invention;

FIGURE 4 is an expanded view of yet another form of the invention; and

FIGURE 5 is a fragmentary expanded view of still another form of the invention.

A fuel burning appliance which may be an incinerator or a heating unit is generally designated 10, as seen in FIGURE 1. The appliance It includes a housing 11 which is divided by a partition 14 into a combustion chamber 12 and a flue-like section 13 for receiving the products of combustion from the combustion chamber 12. The fluelike section 13 inturncommunicates with a flue 16 and for present purposes may be considered a continuation of the latter within the appliance 10. Additionally, the portion 13 includes a branch 18 to which a suitable barometric draft control may be connected. Of course, it will be appreciated that such a branch could be placed appropriately on the flue 16.

Keyed to the branch 18, in a manner that will be seen hereinafter, is a conduit 20 to which a barometric draft control, generally designated 22, is, in turn, keyed. The barometric draft control 20 may be single acting or double acting and made in any manner well known in the art. For exemplary purposes, the barometric draft control 22 is shown to include a tubular housing 24 in which a control gate 26 is pivotaliy mounted at 28. As seen in FIGURES 2. and 4, suitable means, such as weights 30, are provided to bias the gate 26 about the pivot 28 to a proper position dependent upon the draft requirements of the appliance at any given moment. In the form of barometric draft control 22 exemplarly illustrated, the weight distribution of the gate 26 and the biasing means 30 about the pivot 28 is such that with equal pressure on either side of the gate 26, the latter will be maintained in a vertical attitude. In other words, the center of gravity of the combined assemblage of the gate 26 and the biasing means 30 is such that the center of gravity is below the pivot point 28. Obviously, if the housing 24 were to be rotated 180 within the conduit 26), the center of gravity of the combined assemblage would be above the pivot 28 and the gate would normally swing to a non-vertical attitude. As Will be obvious to those skilled in the art, such an inversion of the housing 24 would so orient the gate 26 that it would not properly regulate the draft in the flue 16, and the barometric draft control 22 would be inoperative. lesser degrees of rotation of the housing will similarly render the control 22 inoperative or, at the very least, impair its effectiveness.

Accordingly, the invention provides means for insuring that a person installing such a barometric draft control on a fuel burning appliance cannot connect the control in such a manner. As best seen in FIGURE 2, one embodiment of the invention includes the provision of a lug or projection 32 on the branch 18 of the appliance and a similar lug or projection 34 on the housing 24 of the barometric draft control 22. Additionally, the conduit is provided with slots 36 and 38 for reception of the lugs 32 and 34, respectively. The positioning of the lugs 32 and 34 with respect to the branch 18 and the housing 24, and the positioning of the slots 36 and 38 on the conduit 20 is arranged such that the conduit 20 may be secured to the branch 18 in only one predetermined manner, and the draft control 22 may be secured to the conduit 20 in only one predetermined manner. The over-all arrangement is such that the barometric draft control 22 can be arranged with respect to the appliance and the flue 18 only in one predetermined manner which is the proper position for operation. In other words, the lugs 32 and 34 and the slots 36 and 38 act as keying means for insuring that the draft control is positioned properly with respect to the appliance 10 and the flue 16 and additionally preclude a connection of the latter to the former in anything but a proper operating position by serving as an obstruction to the insertion of the control 22 or branch 18 into the end of the conduit 20 in any improper position.

Another form of the invention is shown in FIGURE 3. In this form of the invention, the slot 38 in the conduit 20 is replaced by an integrally formed, inwardly turned projection or tab 40. Additionally, the lug 34 on the control 22 is replaced by a slot 42, which, when the control 22 is properly mated with the conduit 20, will receive the tab 40. Similar tabs and slots (not shown) may be formed on the other end of the conduit 20 and on the branch 18. Of course, the over-all arrangement of the tabs 40 and the slots 42 is such as to preclude improper connection of the control 22 to the appliance 10 and the flue 16.

Turning now to FIGURE 4, there is shown another form of a keying means which may be utilizing in practicing the invention. In this form, the branch 18 and the control 22 are formed with apertures 44 and 46, respectively. A modified form of conduit 20' includes inwardly projecting pins 48 and 50 for respective reception in the apertures 44 and 46, respectively. In order to facilitate ready insertion of the pins 48 and 50 into their respective apertures, the conduit 20' is made expansible. This is achieved by forming the conduit 20' out of a piece of sheet metal such that at either end of the conduit 20' there are formed suitable outwardly projecting, opposed,

apertured tabs 52. Suitable tightening means 54, which may be sheet metal screws or nuts and bolts, interconnect the apertured tabs 52, and when tightened, draw the tabs 52 together to cause the conduit 20' to constrict. Intermediate the ends of the conduit 2h, there are provided suitable tongues 56 which overlap each other to substantially seal the abutment of the edges of the piece of sheet metal. To install this form of the invention, it is only necessary to loosen the tightening means 54, such that the pin 48 may be inserted in the aperture 44 and the pin 50 inserted in the aperture 46. The tightening means 54 are then used to draw the tabs 52 together until the conduit 20' is constricted sufficiently to tightly conform to the shape of the branch 18 and the barometric draft control 22. Here again, the apertures 44 an-d 46 and the pins 48 and 50 are arranged such that the draft control 22 can be secured to the appliance 10 only in a proper operative position.

Still another form of the invention is shown in FIG- URE 5. In this form of the invention, the keying means comprise a groove 58 integrally struck in the periphery of the conduit 2% adjacent one end thereof and a complementary groove 6t integrally struck in the housing 24 of the draft control 22. The grooves 58 and 60 are sized such that one will nest within the other when the control 22 is mated with the conduit 20. Similar complementary nesting grooves may be provided on the other end of the conduit 20 and on the branch 18. Again, the grooves are arranged such that the draft control 22 can be connected to the appliance It} only in a proper operating orientation or position.

When the keying means comprise projections that are not integrally formed from the various members, it is desirable that such projections be permanently affixed to the respective member, as by welding or the like, such that they may not be removed to defeat the purpose thereof.

It will, of course, be obvious to those skilled in the art, that if the branch 18 is made of a suitable length, the conduits 20 and 20' may be omitted and the draft control 22 connected directly to the branch 18. Similarly, it will be obvious that the invention is not limited to use with the specific barometric draft control described, which is set forth solely for exemplary purposes, but will find substantial utility in any installation wherein a barometric draft control has a gate biasing means that may be rendered partially or Wholly inoperative if improperly oriented with respect to the appliance on which it is installed. Finally, it will be appreciated that the various mechanical expedients used to form the keying means on the branch 18, the conduit 26) and the barometric draft control 22 may be reversed in their positions with respect to one another. For example, it is readily apparent that the grooves 36 and 38, shown in FIGURE 2, may be placed on the branch 18 and the control 22 rather than on the conduit 2%, if the projections 32 and 34 are appropriately placed on the conduit 20. Furthermore, such a reversal may be made only with respect to the conduit 20 and the control 22 While maintaining the illustrated arrangement as regards the conduit 20 and the branch 18. Similar alterations may be made with respect to the forms of the invention shown in FIGURES 3, 4 and 5. Accordingly, all such changes and modifications within the skill of one knowledgeable in the art are to be conto have my invention construed broadly according to the true spirit thereof as set forth in the following claims.

I claim:

1. In combination,

(a) fuel burning means wherein products of combustion are generated,

(b) flue means operatively connected to said fuel burning means for receiving the products of combustion generated therein,

(c) barometric draft control means connected to one of said fuel burning means and said flue means for regulating the draft in said flue means,

(d) said barometric draft control means having a proper position of connection relative to said fuel burning means and said flue means for regulating the draft in said flue means and an improper ineffectual position of connection relative to said fuel burning means and said flue means wherein said barometric draft control means does not effectively regulate the draft in said flue means, and

(e) keying means on at least one of said means for insuring that said barometric draft control means is connected to one of said flue means and said fuel burning means only in said proper draft regulating position and for precluding connection of said barometric draft control means to one of said flue means and said fuel burning means in said improper ineffectual position.

2. The combination of claim 1 wherein said keying means comprises a lug received in a slot.

3. The combination of claim 1 wherein said keying means comprises a pin received in an aperture.

4. The combination of claim 1 wherein said keying means comprises a tab received in a slot.

5. The combination of claim 1 wherein said keying means comprises a pair of nesting, complementary grooves.

6. A new article of manufacture for use in an assemblage comprising a fuel burning appliance wherein products of combustion are generated and in which said products of combustion are received by a flue connected to the appliance, said assemblage requiring a barometric draft control for regulating the draft in the flue such that the assemblage may be properly operated, said article comprising:

(a) a tubular housing,

(b) a gate pivotally mounted within said housing,

(0) means operatively connected to said gate for controlling the position of said gate within said housing according to the draft requirements of the assemblage to which the housing is to be attached,

(d) said control means being effective to ultimately regulate the draft for a proper position of said housing relative to the assemblage to which it may be attached, and being ineffective to regulate the draft for an improper position of said housing relative to such an assemblage, and

(e) means on said housing for keying said housing to such an assemblage only in said proper position and for precluding attachment of said housing to an assemblage in said improper position;

7. The article of claim 6 wherein said keying means comprises an aperture adapted to receive a pin.

8. The article of claim 6 wherein said keying means comprises a projection adapted to be received in a slot.

9. The article of claim 6 wherein said keying means comprises a groove adapted to nest with a complementary groove.

10. The article of claim 6 wherein said keying means comprises a slot adapted to receive a tab.

11. The article of claim 6 wherein said keying means comprises an element immovably aflixed to said housing.

12. In a control device for use in an assemblage having a fuel burning appliance wherein products of combustion are generated and in which said products of combustion are received by a flue connected to the appliance, said assemblage requiring a barometric draft control for regulating the draft in the flue such that the assemblage may be properly operated, the combination comprising:

(a) a barometric draft control comprised of a first tube having a gate pivotally mounted therein and biasing means operatively connected to the gate for controlling the position of the gate within said first tube according to the draft requirements of the appliance of the assemblage, said biasing means being aflectable by gravity and rendered at least partially ineffectual for improper positions of said first tube on said assemblage;

(b) a second tube adapted to be nested with said first tube;

(c) the peripheries of said tubes being of generally similar shape and size for telescoping such that the outer surface of one tube Will be substantially in contact with the inner surface of the other tube when the tubes are nested;

(d) an element immovably fixed to one of said surfaces at a predetermined location thereon and extending toward the other of said surfaces a distance greater than the distance between said surfaces when said tubes are nested;

(e) an immovably fixed relieved portion at a predetermined location on said other of said surfaces for receiving said element whereby said other of said surfaces will block nesting movement of said tubes toward each other for all rotative positions of one to the other except for a predetermined position wherein said element will be received in said relieved portion; and

(f) said predetermined locations of said element and said relieved portion being chosen such that said predetermined position is the proper operating position for said barometric draft control whereby said barometric draft control cannot be installed on said assemblage in a position wherein gravity may render said biasing means ineffectual.

References Cited UNITED STATES PATENTS 183,315 10/1876 Mainer 285-424 X 521,959 6/1894 Huntress 285-424 X 1,004,004 9/1911 Farrell 285-419 1,051,461 1/1913 Smith 285-424 X 1,217,805 2/1917 Meyers 285-424 X 1,255,417 2/1918 Hedges 285-419 1,628,644 5/1927 Breese 236-45 2,079,804 5/1937 Jones 236-45 2,182,625 12/1939 Field 236-45 2,388,253 11/1945 Dady 236-45 WILLIAM J. WYE, Primary Examiner. ALDEN D. STEWART, Examiner. 

1. IN COMBINATION, (A) FUEL BURNING MEANS WHEREIN PRODUCTS OF COMBUSTION ARE GENERATED, (B) FLUE MEANS OPERATIVELY CONNECTED TO SAID FUEL BURNING MEANS FOR RECEIVING THE PRODUCTS OF COMBUSTION GENERATED THEREIN, (C) BAROMETRIC DRAFT CONTROL MEANS CONNECTED TO ONE OF SAID FUEL BURNING MEANS AND SAID FLUE MEANS FOR REGULATING THE DRAFT IN SAID FLUE MEANS, (D) SAID BAROMETRIC DRAFT CONTROL MEANS HAVING A PROPER POSITION OF CONNECTION RELATIVE TO SAID FUEL BURNING MEANS AND SAID FLUE MEANS FOR REGULATING THE DRAFT IN SAID FLUE MEANS AND AN IMPROPER INEFFECTUAL POSITION OF CONNECTION RELATIVE TO SAID FUEL BURNING MEANS AND SAID FLUE MEANS WHEREIN SAID BAROMETRIC DRAFT CONTROL MEANS DOES NOT EFFECTIVELY REGULATE THE DRAFT IN SAID FLUE MEANS, AND (E) KEYING MEANS ON AT LEAST ONE OF SAID MEANS FOR INSURING THAT SAID BAROMETRIC DRAFT CONTROL MEANS IS CONNECTED TO ONE OF SAID FLUE MEANS AND SAID FUEL BURNING MEANS ONLY IN SAID PROPER DRAFT REGULATING POSITION AND FOR PRECLUDING CONNECTION OF SAID BAROMETRIC DRAFT CONTROL MEANS TO ONE OF SAID FLUE MEANS AND SAID FUEL BURNING MEANS IN SAID IMPROPER INEFFECTUAL POSITION. 